Certain activities or professions are associated with recognizable outfits. With Costume Inertia, this will be depicted with the most outlandish, extreme, or just plain fetishistic version of said outfit, even if the character otherwise wears a normal outfit most of the time. Sometimes the character will forget and just keep wearing the outfit long after it's needed, or will even seem not to remember putting it on. Often, this is done tongue-in-cheek by artists who really only want an excuse to put characters in fun costumes, but is a very good indicator to the general 'serious' mood and focus of a series. It generally runs:
Mundane -> Stylized -> Noticeable -> Overboard
Ironically, having slightly less-than-maximum Costume Inertia doesn't always work, since it implies designers know just enough about the minor details of an outfit and put just enough time into it that they probably have a personal jones for it.
Occasionally the trope is played with in an Unreveal, where the 'normal' outfit appears instead of the predicted one - much to the disappointment of another character.
Anime and Manga
- Occured in Love Hina, where Motoko's breakdown after a fight with her sister persuades her to become the inn's housekeeper, wearing a full maid outfit in her size.
- .hack//Legend of the Twilight Bracelet somehow manages a Beach Episode that subverts this, where Shugo suddenly realizes that Ouka, being a Cool Big Sis, should naturally appear in the slinkiest swimsuit of any of the girls—until she shows up in wolf shape (which, granted, means she's technically naked).
- In He Is My Master, a guest character agrees to have a competition with the show's resident lech. The former excels at designing several costumes with noticeably less Costume Inertia than the latter, before the lead girl is convinced there's not enough of a functional difference to bother changing employers. (That and the new employer loves crossdressing, which is a step too far for the girl who gets abused on a daily basis by every other main character.)
- The ending of the Tokyo Mew Mew manga requires a wedding dress anyway... but why a short, frilly, lace-and-ribbon-covered, giant-strawberry-adorned number, especially when supposedly thrown together in a short amount of time? Simply because it's cute.
- All of the Cutie Honey shows/movies.
- Anything with a "Magical Girl" who's old enough to have noticeable breasts.
- Dirty Pair Flash had Kei go through a literally bra-bursting transformation sequence in the first episode, never seen again.
- Applied in Magical Girl Lyrical Nanoha in the third season, where Nanoha and Fate change their previously more mundane Magical Girl uniforms for slightly more complicated and extravagant versions (though Fate was actually downgraded from her infamous previous outfit). This time, however, it's more indicative of Nanoha and Fate growing up 10 years and thus outgrowing their nine-year-old selves, and ultimately they switch back to the old outfits two thirds of the way in, mostly to indicate they're getting serious.
- Franco-Belgian comic character Spirou kept his hotel groom outfit for a very long time of the series, even if he had become a reporter and had no reasons to still wear it.
- Donald Duck still wears the sailor suit. He debuted as a young duck in the thirties (when this style was humorously outdated). Some comics do make him an actual sailor, though strangely enough not the Barks/Don Rosa canon. He even wore it in a 1941 short when he was Drafted into the Army. It was replaced with an army uniform, but still looks really bizarre.
- Empowered's "Hot Librarian" disguise. Inverted with ThugBoy's "Spartan 3000" henchman's uniform.
- ACDC's Angus Young originally became a member of the band while he was still in high school, and so wore a school uniform - his real one - on stage. Decades later, and he still has his distinctive schoolboy look with full uniform.
- Street Fighter has Sakura Kasugano, pictured above, takes it perhaps too literally. In the Sakura Ganbaru manga, she justified fighting in her school uniform as being ready to fight at any time. Thusly, being a student, she wanted to be ready to fight in clothes she spent much of her day wearing. By Street Fighter IV, Sakura has since graduated, but as you can see still wears the uniform to fight. However, at the end of said manga she wears a different uniform - because she's a PE teacher now. And since it's an alternate costume for her in IV, this is evidently the case there as well.
- In the opening of Chuck Rock, Chuck's Loin Cloth is in the wash, so he puts on some leaves instead. He's still wearing those leaves in the sequel, which takes place years later.
- In Raidou Kuzunoha vs. the Soulless Army Raidou Kuzunoha is 17 and was, until his current apprenticeship/cover, a student, hence his school uniform. Raidou Kuzunoha VS King Abaddon may or may not take place 3 years latter (A character that loves to break the fourth wall says you haven't met for 3 years and the games have a release gap of 3 years and the characters all act like noticeable time has passed), but Raidou still wears the uniform.
- Reimu of Touhou originally wore a realistic Miko outfit, however after the Continuity Reboot she switched to a more stylised and less practical version, complete with Detached Sleeves. Sanae also wears a similar outfit.